The global distribution of atmospheric methyl bromide (CH3Br) obtained from extensive new measurements of atmospheric CH3Br from latitude 82.5 ¿N to 69.1 ¿S, showed a small decrease from mid-to high-latitudes, a gradient between the northern and southern hemispheres with a ratio of 1.2 to 1.3, and occasional high concentrations in the tropics. The observed data and modeled distributions of industrial CH3Br were used to apportion CH3Br between natural and industrial components for both hemisphere. We obtained an estimated man-made contribution of 4.3 pptv and 2.3 pptv in the northern and southern hemispheres, respectively and a natural (non-industrial) background concentration in both hemispheres of 6 pptv with a slight increase in the tropics. ¿ 2000 American Geophysical Union